Hybrid maize plant and seed (39K72)

ABSTRACT

According to the invention, there is provided a hybrid maize plant, designated as 39K72, produced by crossing two Pioneer Hi-Bred International, Inc. proprietary inbred maize lines. This invention relates to the hybrid seed 39K72, the hybrid plant produced from the seed, and variants, mutants, and trivial modifications of hybrid 39K72.

FIELD OF THE INVENTION

This invention is in the field of maize breeding, specifically relatingto a hybrid maize line designated 39K72.

BACKGROUND OF THE INVENTION Plant Breeding

Field crops are bred through techniques that take advantage of theplant's method of pollination. A plant is self-pollinated if pollen fromone flower is transferred to the same or another flower of the sameplant. A plant is cross-pollinated if the pollen comes from a flower ona different plant.

Plants that have been self-pollinated and selected for type for manygenerations become homozygous at almost all gene loci and produce auniform population of true breeding progeny. A cross between twodifferent homozygous lines produces a uniform population of hybridplants that may be heterozygous for many gene loci. A cross of twoplants each heterozygous at a number of gene loci will produce apopulation of hybrid plants that differ genetically and will not beuniform.

Maize (Zea mays L.), often referred to as corn in the United States, canbe bred by both self-pollination and cross-pollination techniques. Maizehas separate male and female flowers on the same plant, located on thetassel and the ear, respectively. Natural pollination occurs in maizewhen wind blows pollen from the tassels to the silks that protrude fromthe tops of the ears.

The development of a hybrid maize variety involves three steps: (1) theselection of plants from various germplasm pools for initial breedingcrosses; (2) the selfing of the selected plants from the breedingcrosses for several generations to produce a series of inbred lines,which, although different from each other, breed true and are highlyuniform; and (3) crossing the selected inbred lines with unrelatedinbred lines to produce the hybrid progeny (F₁). During the inbreedingprocess in maize, the vigor of the lines decreases. Vigor is restoredwhen two different inbred lines are crossed to produce the hybridprogeny (F₁). An important consequence of the homozygosity andhomogeneity of the inbred lines is that the hybrid created by crossing adefined pair of inbreds will always be the same. Once the inbreds thatcreate a superior hybrid have been identified, a continual supply of thehybrid seed can be produced using these inbred parents and the hybridcorn plants can then be generated from this hybrid seed supply.

Large scale commercial maize hybrid production, as it is practicedtoday, requires the use of some form of male sterility system whichcontrols or inactivates male fertility. A reliable method of controllingmale fertility in plants also offers the opportunity for improved plantbreeding. This is especially true for development of maize hybrids,which relies upon some sort of male sterility system. There are severaloptions for controlling male fertility available to breeders, such as:manual or mechanical emasculation (or detasseling), cytoplasmic malesterility, genetic male sterility, gametocides and the like.

Hybrid maize seed is typically produced by a male sterility systemincorporating manual or mechanical detasseling. Alternate strips of twoinbred varieties of maize are planted in a field, and the pollen-bearingtassels are removed from one of the inbreds (female) prior to pollenshed. Providing that there is sufficient isolation from sources offoreign maize pollen, the ears of the detasseled inbred will befertilized only from the other inbred (male), and the resulting seed istherefore hybrid and will form hybrid plants.

The laborious, and occasionally unreliable, detasseling process can beavoided by using cytoplasmic male-sterile (CMS) inbreds. Plants of a CMSinbred are male sterile as a result of factors resulting from thecytoplasmic, as opposed to the nuclear, genome. Thus, thischaracteristic is inherited exclusively through the female parent inmaize plants, since only the female provides cytoplasm to the fertilizedseed. CMS plants are fertilized with pollen from another inbred that isnot male-sterile. Pollen from the second inbred may or may notcontribute genes that make the hybrid plants male-fertile. Usually seedfrom detasseled fertile maize and CMS produced seed of the same hybridare blended to insure that adequate pollen loads are available forfertilization when the hybrid plants are grown.

There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. Theseand all patents referred to are incorporated by reference. In additionto these methods, Albertsen et al., of Pioneer Hi-Bred, U.S. patentapplication Ser. No. 07/848,433, have developed a system of nuclear malesterility which includes: identifying a gene which is critical to malefertility; silencing this native gene which is critical to malefertility; removing the native promoter from the essential malefertility gene and replacing it with an inducible promoter; insertingthis genetically engineered gene back into the plant; and thus creatinga plant that is male sterile because the inducible promoter is not "on"resulting in the male fertility gene not being transcribed. Fertility isrestored by inducing, or turning "on", the promoter, which in turnallows the gene that confers male fertility to be transcribed.

There are many other methods of conferring genetic male sterility in theart, each with its own benefits and drawbacks. These methods use avariety of approaches such as delivering into the plant a gene encodinga cytotoxic substance associated with a male tissue specific promoter oran antisense system in which a gene critical to fertility is identifiedand an antisense to that gene is inserted in the plant (see:Fabinjanski, et al. EPO 89/3010153.8 publication no. 329,308 and PCTapplication PCT/CA90/00037 published as WO 90/08828).

Another system useful in controlling male sterility makes use ofgametocides. Gametocides are not a genetic system, but rather a topicalapplication of chemicals. These chemicals affect cells that are criticalto male fertility. The application of these chemicals affects fertilityin the plants only for the growing season in which the gametocide isapplied (see Carlson, Glenn R., U.S. Pat. No. 4,936,904). Application ofthe gametocide, timing of the application and genotype specificity oftenlimit the usefulness of the approach.

The use of male sterile inbreds is but one factor in the production ofmaize hybrids. The development of maize hybrids requires, in general,the development of homozygous inbred lines, the crossing of these lines,and the evaluation of the crosses. Breeding programs combine the geneticbackgrounds from two or more inbred lines or various other broad-basedsources into breeding pools from which new inbred lines are developed byselfing and selection of desired phenotypes. The new inbreds are crossedwith other inbred lines and the hybrids from these crosses are evaluatedto determine which of those have commercial potential.

There are many important factors to be considered in the art of plantbreeding, such as the ability to recognize important morphological andphysiological characteristics, the ability to design evaluationtechniques for genotypic and phenotypic traits of interest, and theability to search out and exploit the genes for the desired traits innew or improved combinations.

The objective of commercial maize hybrid line development programs is todevelop new inbred lines to produce hybrids that combine to produce highgrain yields and superior agronomic performance. The primary traitbreeders seek is yield. However, many other major agronomic traits areof importance in hybrid combination and have an impact on yield orotherwise provide superior performance in hybrid combinations. Suchtraits include percent grain moisture at harvest, relative maturity,resistance to stalk breakage, resistance to root lodging, grain quality,and disease and insect resistance. In addition, the lines per se musthave acceptable performance for parental traits such as seed yields,kernel sizes, pollen production, all of which affect ability to provideparental lines in sufficient quantity and quality for hybridization.These traits have been shown to be under genetic control and many if notall of the traits are affected by multiple genes.

Pedigree Breeding

The pedigree method of breeding is the mostly widely used methodologyfor new hybrid line development.

In general terms this procedure consists of crossing two inbred lines toproduce the non-segregating F₁ generation, and self pollination of theF₁ generation to produce the F₂ generation that segregates for allfactors for which the inbred parents differ. An example of this processis set forth below. Variations of this generalized pedigree method areused, but all these variations produce a segregating generation whichcontains a range of variation for the traits of interest.

EXAMPLE 1.

Hypothetical Example of Pedigree Breeding Program

Consider a cross between two inbred lines that differ for alleles at sixloci. The parental genotypes are:

    ______________________________________    Parent 1         A b C d e F/A b C d e F    Parent 2         a B c D E f/a B c D E f    ______________________________________

the F₁ from a cross between these two parents is:

    ______________________________________    F.sub.1         A b C d e F/a B c D E f    ______________________________________

Selfing F₁ will produce an F₂ generation including the followinggenotypes:

A B c D E f/a b C d e F

A B c D e f/a b C d E F

A B c D e f/a b C d e F

The number of genotypes in the F₂ is 3⁶ for six segregating loci (729)and will produce (2⁶)-2 possible new inbreds, (62 for six segregatingloci).

Each inbred parent which is used in breeding crosses represents a uniquecombination of genes, and the combined effects of the genes define theperformance of the inbred and its performance in hybrid combination.There is published evidence (Smith, O. S., J. S. C. Smith, S. L. Bowen,R. A. Tenborg and S. J. Wall, TAG 80:833-840 (1990)) that each of thelines are different and can be uniquely identified on the basis ofgenetically-controlled molecular markers.

It has been shown (Hallauer, Arnel R. and Miranda, J. B. Fo.Quantitative Genetics in Maize Breeding, Iowa State University Press,Ames Iowa, 1981) that most traits of economic value in maize are underthe genetic control of multiple genetic loci, and that there are a largenumber of unique combinations of these genes present in elite maizegermplasm. If not, genetic progress using elite inbred lines would nolonger be possible. Studies by Duvick and Russell (Duvick, D. N.,Maydica 37:69-79, (1992); Russell, W. A., Maydica XXIX:375-390 (1983))have shown that over the last 50 years the rate of genetic progress incommercial hybrids has been between one and two percent per year.

The number of genes affecting the trait of primary economic importancein maize, grain yield, has been estimated to be in the range of 10-1000.Inbred lines which are used as parents for breeding crosses differ inthe number and combination of these genes. These factors make the plantbreeder's task more difficult. Compounding this is evidence that no oneline contains the favorable allele at all loci, and that differentalleles have different economic values depending on the geneticbackground and field environment in which the hybrid is grown. Fiftyyears of breeding experience suggests that there are many genesaffecting grain yield and each of these has a relatively small effect onthis trait. The effects are small compared to breeders' ability tomeasure grain yield differences in evaluation trials. Therefore, theparents of the breeding cross must differ at several of these loci sothat the genetic differences in the progeny will be large enough thatbreeders can develop a line that increases the economic worth of itshybrids over that of hybrids made with either parent.

If the number of loci segregating in a cross between two inbred lines isn, the number of unique genotypes in the F₂ generation is 3^(n) and thenumber of unique inbred lines from this cross is {(2^(n))-2}. Only avery limited number of these combinations are useful. Only about 1 in10,000 of the progeny from F₂ 's are commercially useful.

By way of example, if it is assumed that the number of segregating lociin F₂ is somewhere between 20 and 50, and that each parent is fixed forhalf the favorable alleles, it is then possible to calculate theapproximate probabilities of finding an inbred that has the favorableallele at {(n/2)+m} loci, where n/2 is the number of favorable allelesin each of the parents and m is the number of additional favorablealleles in the new inbred. See Example 2 below. The number m is assumedto be greater than three because each allele has so small an effect thatevaluation techniques are not sensitive enough to detect differences dueto three or less favorable alleles. The probabilities in Example 2 areon the order of 10⁻⁵ or smaller and they are the probabilities that atleast one genotype with (n/2)=m favorable alleles will exist.

To put this in perspective, the number of plants grown on 60 millionacres (approximate United States corn acreage) at 25,000 plants/acre is1.5×10¹².

EXAMPLE 2 Probability of Finding an Inbred with m of n FavorableAlleles.

Assume each parent has n/2 of the favorable alleles and only 1/2 of thecombinations of loci area economically useful.

    ______________________________________    No. of   No. of favorable                         No. additional    segregating loci             alleles in Parents                         favorable alleles                                     Probability that    (n)      (n/2)       in new inbred                                     genotype occurs*    ______________________________________    20       10          14          3 × 10.sup.-5    24       12          16          2 × 10.sup.-5    28       14          18          1 × 10.sup.-5    32       16          20          8 × 10.sup.-6    36       18          22          5 × 10.sup.-6    40       20          24          3 × 10.sup.-6    44       22          26          2 × 10.sup.-6    48       24          28          1 × 10.sup.-6    ______________________________________     *Probability that a useful combination exists, does not include the     probability of identifying this combination if it does exist.

The possibility of having a usably high probability of being able toidentify this genotype based on replicated field testing would be mostlikely smaller than this, and is a function of how large a population ofgenotypes is tested and how testing resources are allocated in thetesting program.

SUMMARY OF THE INVENTION

According to the invention, there is provided a hybrid maize plant,designated as 39K72, produced by crossing crossing two Pioneer Hi-BredInternational, Inc. proprietary inbred maize lines. This invention thusrelates to the hybrid seed 39K72₁ the hybrid plant produced from theseed, and varients, mutants and trivial modifications of hybrid 39K72.This hybrid maize plant is characterized by early maturity and good testweight. 39K72 has outstanding seedling vigor and good roots.

DEFINITIONS

In the description and examples that follow, a number of terms are usedherein. In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided. NOTE: ABS is in absolute termsand %MN is percent of the mean for the experiments in which the inbredor hybrid was grown. These designators will follow the descriptors todenote how the values are to be interpreted. Below are the descriptorsused in the data tables included herein.

ANT ROT=ANTHRACNOSE STALK ROT (Colletotrichum graminicola). A 1 to 9visual rating indicating the resistance to Anthracnose Stalk Rot. Ahigher score indicates a higher resistance.

BAR PLT=BARREN PLANTS. The percent of plants per plot that were notbarren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near thetime of pollination, and is an indication of whether a hybrid or inbredwould snap or break near the time of flowering under severe winds. Dataare presented as percentage of plants that did not snap in pairedcomparisons and on a 1 to 9 scale (9=highest resistance) inCharacteristics Charts.

BU ACR=YIELD (BUSHELS/ACRE). Yield of the grain at harvest in bushelsper acre adjusted to 15.5% moisture.

CLN=CORN LETHAL NECROSIS (synergistic interaction of maize chloroticmottle virus (MCMV) in combination with either maize dwarf mosaic virus(MDMV-A or MDMV-B) or wheat streak mosaic virus (WSMV)). A 1 to 9 visualrating indicating the resistance to Corn Lethal Necrosis. A higher scoreindicates a higher resistance.

COM RST=COMMON RUST (Puccinia sorghi). A 1 to 9 visual rating indicatingthe resistance to Common Rust. A higher score indicates a higherresistance.

CRM=COMPARATIVE RELATIVE MATURITY (see PRM).

D/D=DRYDOWN. This represents the relative rate at which a hybrid willreach acceptable harvest moisture compared to other hybrids on a 1-9rating scale. A high score indicates a hybrid that dries relatively fastwhile a low score indicates a hybrid that dries slowly.

D/E=DROPPED EARS. Represented in a 1 to 9 scale in the CharacteristicsChart, where 9 is the rating representing the least, or no, droppedears.

DIP ERS=DIPLODIA EAR MOLD SCORES (Diplodia maydis and Diplodiamacrospora). A 1 to 9 visual rating indicating the resistance toDiplodia Ear Mold. A higher score indicates a higher resistance.

DRP EAR=DROPPED EARS. A measure of the number of dropped ears per plotand represents the percentage of plants that did not drop ears prior toharvest.

D/T=DROUGHT TOLERANCE. This represents a 1-9 rating for droughttolerance, and is based on data obtained under stress conditions. A highscore indicates good drought tolerance and a low score indicates poordrought tolerance.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to thehighest placed developed ear node attachment and is measured in inches.This is represented in a 1 to 9 scale in the Characteristics Chart,where 9 is highest.

EAR MLD=General Ear Mold. Visual rating (1-9 score) where a "1" is verysusceptible and a "9" is very resistant. This is based on overall ratingfor ear mold of mature ears without determining the specific moldorganism, and may not be predictive for a specific ear mold.

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher therating the larger the ear size.

ECB 1LF=EUROPEAN CORN BORER FIRST GENERATION LEAF FEEDING (Ostrinianubilalis). A 1 to 9 visual rating indicating the resistance topreflowering leaf feeding by first generation European Corn Borer. Ahigher score indicates a higher resistance.

ECB 2IT=EUROPEAN CORN BORER SECOND GENERATION INCHES OF TUNNELING(Ostrinia nubilalis). Average inches of tunneling per plant in thestalk.

ECB 2SC=EUROPEAN CORN BORER SECOND GENERATION (Ostrinia nubilalis).

A 1 to 9 visual rating indicating post flowering degree of stalkbreakage and other evidence of feeding by European Corn Borer, SecondGeneration. A higher score indicates a higher resistance.

ECB DPE=EUROPEAN CORN BORER DROPPED EARS (Ostrinia nubilalis). Droppedears due to European Corn Borer. Percentage of plants that did not dropears under second generation corn borer infestation.

E/G=EARLY GROWTH. This represents a 1 to 9 rating for early growth,scored when two leaf collars are visible.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishmentin the spring and represents the number of plants that emerge on perplot basis for the inbred or hybrid.

EYE SPT=Eye Spot (Kabatiella zeae or Aureobasidium zeae). A 1 to 9visual rating indicating the resistance to Eye Spot. A higher scoreindicates a higher resistance.

FUS ERS=FUSARIUM EAR ROT SCORE (Fusarium moniliforme or Fusariumsubglutinans). A 1 to 9 visual rating indicating the resistance toFusarium ear rot. A higher score indicates a higher resistance.

G/A=GRAIN APPEARANCE. Appearance of grain in the grain tank (scored downfor mold, cracks, red streak, etc.).

GDU=Growing Degree Units. Using the Barger Heat Unit Theory, thatassumes that maize growth occurs in the temperature range 50° F.-86° F.and that temperatures outside this range slow down growth; the maximumdaily heat unit accumulation is 36 and the minimum daily heat unitaccumulation is 0. The seasonal accumulation of GDU is a major factor indetermining maturity zones.

GDU PHY=GDU TO PHYSIOLOGICAL MATURITY. The number of growing degreeunits required for an inbred or hybrid line to have approximately 50percent of plants at physiological maturity from time of planting.Growing degree units are calculated by the Barger method.

GDU SHD=GDU TO SHED. The number of growing degree units (GDUs) or heatunits required for an inbred line or hybrid to have approximately 50percent of the plants shedding pollen and is measured from the time ofplanting. Growing degree units are calculated by the Barger Method,where the heat units for a 24-hour period are: ##EQU1##

The highest maximum temperature used is 86° F. and the lowest minimumtemperature used is 50° F. For each inbred or hybrid it takes a certainnumber of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for aninbred line or hybrid to have approximately 50 percent of the plantswith silk emergence from time of planting. Growing degree units arecalculated by the Barger Method as given in GDU SHD definition.

GIB ERS=GIBBERELLA EAR ROT (PINK MOLD) (Gibberella zeae). A 1 to 9visual rating indicating the resistance to Gibberella Ear Rot. A higherscore indicates a higher resistance.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis). A 1 to 9 visual ratingindicating the resistance to Gray Leaf Spot. A higher score indicates ahigher resistance.

GOS WLT=Goss' Wilt (Conynebacterium nebraskense). A 1 to 9 visual ratingindicating the resistance to Goss' Wilt. A higher score indicates ahigher resistance.

GRN APP=GRAIN APPEARANCE. This is a 1 to 9 rating for the generalappearance of the shelled grain as it is harvested based on such factorsas the color of harvested grain, any mold on the grain, and any crackedgrain. High scores indicate good grain quality.

H/POP=YIELD AT HIGH DENSITY. Yield ability at relatively high plantdensities on 1-9 relative rating system with a higher number indicatingthe hybrid responds well to high plant densities for yield relative toother hybrids. A 1, 5, and 9 would represent very poor, average, andvery good yield response, respectively, to increased plant density.

HC BLT=HELMINTHOSPORIUM CARBONUM LEAF BLIGHT (Helminthosporiumcarbonum). A 1 to 9 visual rating indicating the resistance toHelminthosporium infection. A higher score indicates a higherresistance.

HD SMT=HEAD SMUT (Sphacelotheca reiliana). This score indicates thepercentage of plants not infected.

INC DIA=GROSS INCOME (DOLLARS PER ACRE). Relative income per acreassuming drying costs of two cents per point above 15.5 percent harvestmoisture and current market price per bushel.

INCOME/ACRE. Income advantage of hybrid to be patented over other hybridon per acre basis.

INC ADV=GROSS INCOME ADVANTAGE. GROSS INCOME advantage of variety #1over variety #2.

L/POP=YIELD AT LOW DENSITY. Yield ability at relatively low plantdensities on a 1-9 relative system with a higher number indicating thehybrid responds well to low plant densities for yield relative to otherhybrids. A 1, 5, and 9 would represent very poor, average, and very goodyield response, respectively, to low plant density.

MDM CPX=MAIZE DWARF MOSAIC COMPLEX (MDMV=Maize Dwarf Mosaic Virus andMCDV=Maize Chlorofic Dwarf Virus). A 1 to 9 visual rating indicating theresistance to Maize Dwarf Mosaic Complex. A higher score indicates ahigher resistance.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture ofthe grain at harvest.

MST ADV=MOISTURE ADVANTAGE. The moisture advantage of variety #1 overvariety #2 as calculated by: MOISTURE of variety #2 -MOISTURE of variety#1=MOISTURE ADVANTAGE of variety #1.

NLF BLT=Northern Leaf Blight (Helminthosporium turcicum or Exserohilumturcicum). A 1 to 9 visual rating indicating the resistance to NorthernLeaf Blight. A higher score indicates a higher resistance.

PHY CRM=CRM at physiological maturity.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant fromthe ground to the tip of the tassel in inches. This is represented as a1 to 9 scale, 9 highest, in the Characteristics Chart.

POL SC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount ofpollen shed. The higher the score the more pollen shed.

POL WT=POLLEN WEIGHT. This is calculated by dry weight of tasselscollected as cshedding commences minus dry weight from similar tasselsharvested after shedding is complete.

It should be understood that the inbred can, through routinemanipulation of cytoplasmic or other factors, be produced in amale-sterile form. Such embodiments are also contemplated within thescope of the present claims.

POP K/A=PLANT POPULATIONS. Measured as 1000s per acre.

POP ADV=PLANT POPULATION ADVANTAGE. The plant population advantage ofvariety #1 over variety #2 as calculated by PLANT POPULATION of variety#2 -PLANT POPULATION of variety #1=PLANT POPULATION ADVANTAGE of variety#1.

PRM=PREDICTED Relative Maturity. This trait, predicted relativematurity, is based on the harvest moisture of the grain. The relativematurity rating is based on a known set of checks and utilizes standardlinear regression analyses and is referred to as the ComparativeRelative Maturity Rating System that is similar to the MinnesotaRelative Maturity Rating System.

PRM SHD=A relative measure of the growing degree units (GDU) required toreach 50% pollen shed. Relative values are predicted values from thelinear regression of observed GDU's on relative maturity of commercialchecks.

PRO=PROTEIN RATING. Rating on a 1 to 9 scale comparing relative amountof protein in the grain compared to hybrids of similar maturity. A "1"score difference represents a 0.4 point change in grain protein percent(e.g., 8.0% to 8.4%).

P/Y=PROTEIN/YIELD RATING. Indicates, on a 1 to 9 scale, the economicvalue of a hybrid for swine and poultry feeders. This takes into accountthe income due to yield, moisture and protein content.

ROOTS (%)=Percent of stalks NOT root lodged at harvest.

R/L=ROOT LODGING. A 1 to 9 rating indicating the level of root lodgingresistance. The higher score represents higher levels of resistance.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that donot root lodge; plants that lean from the vertical axis as anapproximately 30° angle or greater would be counted as root lodged.

RTL ADV=ROOT LODGING ADVANTAGE. The root lodging advantage of variety #1over variety #2.

S/L=STALK LODGING. A 1 to 9 rating indicating the level of stalk lodgingresistance. The higher scores represent higher levels of resistance.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount ofscatter grain (lack of pollination or kernel abortion) on the ear. Thehigher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amountof vegetative growth after emergence at the seedling stage(approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure ofthe hybrid's worth based on information for up to five traits. A maizebreeder may utilize his or her own set of traits for the selectionindex. One of the traits that is almost always included is yield. Theselection index data presented in the tables represent the mean valueaveraged across testing stations.

SLF BLT=SOUTHERN LEAF BLIGHT (Helminthosporium maydis or Bipolarismaydis). A 1 to 9 visual rating indicating the resistance to SouthernLeaf Blight. A higher score indicates a higher resistance.

SLK CRM=CRM at Silking.

SOU RST=SOUTHERN RUST (Puccinia polysora). A 1 to 9 visual ratingindicating the resistance to Southern Rust. A higher score indicates ahigher resistance.

STA GRN=STAY GREEN. Stay green is the measure of plant health near thetime of black layer formation (physiological maturity). A high scoreindicates better late-season plant health.

STAND (%)=Percent of stalks standing at harvest.

STD ADV=STALK STANDING ADVANTAGE. The advantage of variety #1 overvariety #2 for the trait STK CNT.

STK CNT=NUMBER OF PLANTS. This is the final stand or number of plantsper plot.

STK LDG=STALK LODGING. This is the percentage of plants that did notstalk lodge (stalk breakage) as measured by either natural lodging orpushing the stalks and determining the percentage of plants that breakbelow the ear.

STW WLT=Stewart's Wilt (Erwinia stewarlii). A 1 to 9 visual ratingindicating the resistance to Stewart's Wilt. A higher score indicates ahigher resistance.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure thedegree of blasting (necrosis due to heat stress) of the tassel at thetime of flowering. A 1 would indicate a very high level of blasting attime of flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate therelative size of the tassel. The higher the rating the larger thetassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams)just prior to pollen shed.

TEX EAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate therelative hardness (smoothness of crown) of mature grain. A 1 would bevery soft (extreme dent) while a 9 would be very hard (flinty or verysmooth crown).

TIL LER=TILLERS. A count of the number of tillers per plot that couldpossibly shed pollen was taken. Data is given as a percentage oftillers: number of tillers per plot divided by number of plants perplot.

TST WT (CHARACTERISTICS CHART)=Test weight on a 1 to 9 rating scale witha 9 being the highest rating.

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grainin pounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain inpounds for a given volume (bushel) adjusted for 15.5 percent moisture.

TSW ADV=TEST WEIGHT ADVANTAGE. The test weight advantage of variety #1over variety #2.

WIN M%=PERCENT MOISTURE WINS.

WIN Y%=PERCENT YIELD WINS.

YLD=YIELD. It is the same as BU ACR ABS.

YLD ADV=YIELD ADVANTAGE. The yield advantage of variety #1 over variety#2 as calculated by: YIELD of variety #1 -YIELD variety #2=yieldadvantage of variety #1.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relativerating for yield based on plot ear piles. The higher the rating thegreater visual yield appearance.

DETAILED DESCRIPTION OF THE INVENTION

Pioneer Brand Hybrid 39K72 demonstrates good yield with low harvestmoisture. It has early maturity and early flowering as well as good rootlodging resistance. Hybrid 39K72 also exhibits good test weight andoutstanding seedling vigor.

Pioneer Brand Hybrid 39K72 is a single cross, yellow endosperm, dentmaize hybrid with good yield for its maturity. 39K72 is particularlysuited to the earliest corn growing areas of North America and isespecially adapted to the Prairie Provinces of Canada.

This hybrid has the following characteristics based on the datacollected primarily at Johnston, Iowa.

                                      TABLE 1    __________________________________________________________________________    VARIETY DESCRIPTION INFORMATION    VARIETY = 39K72    __________________________________________________________________________    1. TYPE: (describe intermediate types in Comments section):    2   1 = Sweet 2 = Dent 3 = Flint 4 = Flour 5 = Pop 6 = Ornamental    2. MATURITY:          HEAT    DAYS  UNITS    060   1,024.5               From emergence to 50% of plants in silk    060   1,027.5               From emergence to 50% of plants in pollen    003   0,076.5               From 10% to 90% pollen shed    062   1,1240.0               From 50% silk to harvest at 25% moisture                                               Standard                                                    Sample    3. PLANT:                                  Deviation                                                    Size    0,214.5          cm   Plant Height (to tassel tip)    21.92                                                    2    0,110.0          cm   Ear Height (to base of top ear node)                                               56.57                                                    2    0,015.6          cm   Length of Top Ear internode     0.85 10    1          Average Number of Tillers       0.00 2    1.0        Average Number of Ears per Stalk                                               0.00 2    3.0        Anthocyanin of Brace Roots: 1 = Absent 2 = Faint 3 = Moderate               4 = Dark                                               Standard                                                    Sample    4. LEAF:                                   Deviation                                                    Size    007.8 cm   Width of Ear Node Leaf          0.57 10    067.8 cm   Length of Ear Node Leaf         8.77 10    05.7       Number of leaves above top ear  0.99 10    048.5      Degrees Leaf Angle (measure from 2nd leaf above                                               4.95 2               ear at anthesis to stalk above leaf)    03         Leaf Color                         Dark Green                                (Munsell code)                                          5GY44    1.5        Leaf Sheath Pubescence (Rate on scale from 1 = none to 9 =               like peach fuzz)    7.0        Marginal Waves (Rate on scale from 1 = none to 9 = many)    6.0        Longitudinal Creases (Rate on scale from 1 = none to 9 =               many)                                               Standard                                                    Sample    5. TASSEL:                                 Deviation                                                    Size    08.4       Number of Primary Lateral Branches                                               1.41 10    062.5      Branch Angle from Central Spike 17.68                                                    2    56.0  cm   Tassel Length (from top leaf collar to tassel                                               1.70 2    8.0        Pollen Shed (rate on scale from 0 = male sterile to 9 = heavy               shed)    11         Anther Color                         Pink   (Munsell code)                                          10RP74    01         Glume Color                         Light Green                                (Munsell code)                                          5GY66    1.0        Bar Glumes (Glume Bands): 1 = Absent 2 = Present    20         Peduncle Length (cm. from top leaf to basal branches)    6a. EAR (Unhusked Data):    11         Silk Color (3 days after emergence)                                            Pink   (Munsell                                                          5R66)    2          Fresh Husk Color (25 days after 50% silking)                                            Medium Green                                                   (Munsell                                                          5GY68    21         Dry Husk Color (65 days after 50% silking)                                            Buff   (Munsell                                                          2.5Y84    3          Position of Ear at Dry Husk Stage: 1 = Upright 2 = Horizontal               3 = Pendant                                Pendant    4          Husk Tightness (Rate of Scale from 1 = very loose to 9 = very               tight)    2          Husk Extension (at harvest): 1 = Short (ears exposed) 2 =               Medium (<8 cm)               3 = Long (8-10 cm beyond ear tip) 4 = Very Long (>10                                                          Medium                                               Standard                                                    Sample    6b. EAR (Husked Ear Data):                 Deviation                                                    Size    19    cm   Ear Length                      2.12 10    42    mm   Ear Diameter at mid-point       2.83 10    147   gm   Ear Weight                      42.43                                                    10    15         Number of Kernel Rows           0.71 10    2          Kernel Rows: 1 = Indistinct 2 = Distinct   Distinct    1          Row Alignment: 1 = Straight 2 = Slightly Curved 3                                                          Straight    19    cm   Shank Length                    4.95 10    2          Ear Taper: 1 = Slight 2 = Average 3 = Extreme                                                          Average                                               Standard                                                    Sample    7. KERNEL (Dried):                         Deviation                                                    Size    11    mm   Kernel Length                   0.71 10    8     mm   Kernel Width                    0.00 10    5     mm   Kernel Thickness                0.71 10    8          % Round Kernels (Shape Grade)        1    1          Aleurone Color Pattern: 1 = Homozygous 2 = Segregating                                                          Homozygous    7          Aluerone Color                         Yellow (Munsell code)                                          10YR714    7          Hard Endosperm Color                         Yellow (Munsell code)                                          10YR814    3          Endosperm Type:                         Normal Starch               1 = Sweet (Su1) 2 = Extra Sweet (sh2) 3 = Normal Starch               4 = High Amylose Starch 5 = Waxy Starch 6 = High Protein               7 = High Lysine 8 = Super Sweet (se) 9 = High Oil               10 = Other    26    gm   Weight per 100 Kernels (unsized sample)                                               4.24 2                                               Standard                                                    Sample    8. COB:                                    Deviation                                                    Size    26    mm   Cob Diameter at mid-point       2.12 10    14         Cob Color Red    (Munsell code)                                          5R58    9. DISEASE RESISTANCE (Rate from 1 (most susceptible) to 9 (most    resistant): leave blank                if not tested: leave Race or Strain Options blank if                polygenic):    A. Leaf Blights, Wilts, and Local Infection Diseases          Anthracnose Leaf Blight (Colletotrichum graminicola)          Common Rust (Puccinia sorghi)          Common Smut (Ustilago maydis)    6     Eyespot (Kabatiella zeae)    2     Goss's Wilt (Clavibacter michiganense spp. nebraskense)          Gray Leaf Spot (Cercospora zeae-maydis)          Helminthosporium Leaf Spot (Bipolaris zeicola) Race    4     Northern Leaf Blight (Exserohilum turcicum) Race          Southern Leaf Blight (Bipolaris maydis) Race          Southern Rust (Puccinia polysora)          Stewart's Wilt (Erwinia stewartii)          Other (Specify)    B. Systemic Diseases          Corn Lethal Necrosis (MCMV and MDMV)          Head Smut (Sphacelotheca reiliana)          Maize Chlorotic Dwarf Virus (MDV)          Maize Chlorotic Mottle Virus (MCMV)          Maize Dwarf Mosaic Virus (MDMV)          Sorghum Downy Mildew of Corn (Peronosclerospora sorghi)          Other (Specify)    C. Stalk Rots          Anthracnose Stalk Rot (Colletotrichum graminicola)          Diplodia Stalk Rot (Stenocarpella maydis)          Fusarium Stalk Rot (Fusarium moniliforme)          Gibberella Stalk Rot (Gibberella zeae)          Other (Specify)    D. Ear and Kernel Rots          Aspergillus Ear and Kernel Rot (Aspergillus flavus)          Diplodia Ear Rot (Stenocarpella maydis)          Fusarium Ear and Kernel Rot (Fusarium moniliforme)    6     Gibberella Ear Rot (Gibberella zeae)          Other (Specify)          Banks grass Mite (Oligonychus pratensis)          Corn Worm (Helicoverpa zea)           Leaf Feeding           Silk Feeding            mg larval wt.          Ear Damage          Corn Leaf Aphid (Rhopalosiphum maidis)          Corn Sap Beetle (Carpophilus dimidiatus           European Corn Borer (Ostrinia nubilalis)    5      1st Generation (Typically Whorl Leaf Feeding)    4      2nd Generation (Typically Leaf Sheath-Collar Feeding)           Stalk Tunneling           cm tunneled/plant          Fall Armyworm (Spodoptera fruqiperda)           Leaf Feeding           Silk Feeding           mg larval wt.          Maize Weevil (Sitophilus zeamaize          Northern Rootworm (Diabrotica barberi)          Southern Rootworm (Diabrotica undecimpunctata)          Southwestern Corn Borer (Diatreaea grandiosella)           Leaf Feeding           Stalk Tunneling           cm tunneled/plant          Two-spotted Spider Mite (Tetranychus urticae)          Western Rootworm (Diabrotica virgifrea virgifera)          Other (Specify)    11. AGRONOMIC TRAITS:    4          Staygreen (at 65 days after anthesis) (Rate on a scale from 1               = worst to               excellent)    0.2        % Dropped Ears (at 65 days after anthesis)               % Pre-anthesis Brittle Snapping               % Pre-anthesis Root Lodging    4.0        Post-anthesis Root Lodging (at 65 days after anthesis)    6,980      Kg/ha Yield (at 12-13% grain moisture)    __________________________________________________________________________

Research Comparisons for Pioneer Hybrid 39K72

Comparisons of characteristics of Pioneer Brand Hybrid 39K72 were madeagainst Pioneer Brand Hybrids 3970, 3979, and 3984; all of which aresimilarly adapted to hybrid 39K72.

Table 2A compares Pioneer Hybrid 39K72 and Pioneer Hybrid 3970. Theresults show that 39K72 is significantly earlier maturing than hybrid3970 with significantly fewer growing degree units to silk and to shedand a significantly lower predicted relative maturity than hybrid 3970.The 39K72 hybrid demonstrates a lower yield but also shows significantlylower harvest moisture and a significantly higher test weight thanhybrid 3970. The 39K72 hybrid demonstrates significantly superiorseedling vigor than 3970. Both hybrids exhibit good resistance to rootlodging.

Table 2B compares Pioneer Brand Hybrid 39K72 and Pioneer Hybrid 3979. Ascan be seen by the results both hybrids exhibit above average yield withthe 39K72 hybrid demonstrating significantly lower harvest moisture anda significantly higher test weight than 3979. The 39K72 hybriddemonstrates a significantly higher seedling vigor score andsignificantly lower ear placement than the 3979 hybrid. Both hybridsdemonstrate above average brittle snap resistance.

Table 2C compares Pioneer Hybrid 39K72 with Pioneer Hybrid 3984. Theresults show that hybrid 39K72 is significantly higher yielding withsignificantly lower harvest moisture than hybrid 3984. The 39K72 hybridis later maturing with significantly more growing degree units to pollenshed and to silk than the 3984 hybrid. Hybrid 39K72 demonstratessuperior seedling vigor and somewhat superior resistance to root lodgingcompared to hybrid 3984.

                                      TABLE 2A    __________________________________________________________________________    HYBRID COMPARISON REPORT    VARIETY #1 = 39K72    VARIETY #2 = 3970    __________________________________________________________________________                   PRM BU  BU      TST SDG EST GDU               PRM SHD ACR ACR MST WT  VGR CNT SHD               ABS ABS ABS % MN                               % MN                                   ABS % MN                                           % MN                                               % MN    __________________________________________________________________________    TOTAL SUM           1   75  78  113.1                           94  91  56.3                                       106 103 95           2   77  80  115.5                           97  95  55.3                                       80  100 99           LOCS               11  10  46  46  46  16  61  26  31           REPS               11  10  70  70  70  31  103 49  56           DIFF               2   2   2.4 2   4   1.0 26  3   4           PR > T               .000#                   .006#                       .328                           .252                               .000#                                   .000#                                       .000#                                           .085*                                               .000#    __________________________________________________________________________               GDU STK PLT EAR RT  STA STK BRT DRP               SLK CNT HT  HT  LDG GRN LDG STK EAR               % MN                   % MN                       % MN                           % MN                               % MN                                   % MN                                       % MN                                           % MN                                               % MN    __________________________________________________________________________    TOTAL SUM           1   96  99  97  90  103 83  96  117 100           2   98  100 101 95  100 86  94  115 100           LOCS               21  96  38  38  23  26  29  4   10           REPS               37  181 66  66  45  52  57  7   17           DIFF               2   1   4   4   3   3   2   2   0           PR > T               .000#                   .295                       .000#                           .002#                               .103                                   .304                                       .436                                           .223                                               .999    __________________________________________________________________________               NLF  GOS HD   GIB EYE  ECB ECB  ECB               BLT  WLT SMT  ERS SPT  DPE 1LF  2SC               ABS  ABS ABS  ABS ABS  ABS ABS  ABS    __________________________________________________________________________    TOTAL SUM           1   3.0  1.8 95.0 5.5 6.8  94.7                                          4.7  4.3           2   3.6  1.7 99.4 4.8 6.3  92.3                                          5.7  2.7           LOCS               4    3   2    2   2    5   3    3           REPS               8    6   6    4   4    10  3    3           DIFF               0.6  0.2 4.4  0.8 0.5  2.4 1.0  1.7           PR > T               .015+                    .423                        .279 .656                                 .500 .263                                          .225 .038+    __________________________________________________________________________     * = 10% SIG     + = 5% *SIG     # = 1% SIG

                                      TABLE 2B    __________________________________________________________________________    HYBRID COMPARISON REPORT    VARIETY #1 = 39K72    VARIETY #2 = 3979    __________________________________________________________________________                   PRM BU  BU      TST SDG EST GDU               PRM SHD ACR ACR MST WT  VGR CNT SHD               ABS ABS ABS % MN                               % MN                                   ABS % MN                                           % MN                                               % MN    __________________________________________________________________________    TOTAL SUM           1   75  78  113.9                           102 93  56.0                                       111 103 96           2   76  76  115.2                           103 97  54.3                                       100 103 95           LOCS               7   8   29  29  29  21  25  27  13           REPS               7   8   48  48  48  37  43  46  24           DIFF               2   1   1.3 1   4   1.8 11  0   1           PR > T               .003#                   .018+                       .533                           .512                               .000#                                   .000#                                       .019+                                           .999                                               .021+    __________________________________________________________________________               GDU STK PLT EAR RT  STA STK BRT GRN               SLK CNT HT  HT  LDG GRN LDG STK APP               % MN                   % MN                       % MN                           % MN                               % MN                                   % MN                                       % MN                                           % MN                                               % MN    __________________________________________________________________________    TOTAL SUM           1   97  99  99  96  105 82  96  107 100           2   96  100 101 101 91  98  99  105 113           LOCS               10  46  21  21  8   21  28  5   4           REPS               19  86  41  41  14  38  49  5   5           DIFF               1   1   2   5   14  16  3   2   13           PR > T               .070*                   .368                       .062*                           .006#                               .256                                   .019+                                       .144                                           .374                                               .076*    __________________________________________________________________________               DRP NLF GOS HD  GIB EYE ECB ECB ECB               EAR BLT WLT SMT ERS SPT DPE 1LF 2SC               % MN                   ABS ABS ABS ABS ABS ABS ABS ABS    __________________________________________________________________________    TOTAL SUM           1   100 3.0 1.8 91.7                               5.5 5.5 99.0                                           4.7 4.3           2   100 3.7 4.7 84.0                               6.0 6.5 97.4                                           6.7 3.7           LOCS               18  3   3   2   2   1   1   3   3           REPS               26  6   5   5   3   2   2   3   3           DIFF               0   0.7 2.8 7.7 0.5 1.0 1.6 2.0 0.7           PR > T               .999                   .184                       .042+                           .323                               .795        .184                                               .423    __________________________________________________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 2C    __________________________________________________________________________    HYBRID COMPARISON REPORT    VARIETY #1 = 39K72    VARIETY #2 = 3984    __________________________________________________________________________                   PRM BU  BU      TST SDG EST GDU               PRM SHD ACR ACR MST WT  VGR CNT SHD               ABS ABS ABS % MN                               % MN                                   ABS % MN                                           % MN                                               % MN    __________________________________________________________________________    TOTAL SUM           1   75  78  108.9                           100 94  56.0                                       111 103 95           2   76  75  93.5                           86  96  56.2                                       105 103 93           LOCS               7   10  30  30  30  20  29  32  17           REPS               7   10  50  50  50  36  51  56  33           DIFF               1   3   15.4                           14  3   0.2 7   0   2           PR > T               .105                   .002#                       .000#                           .000#                               .006#                                   .245                                       .083*                                           .999                                               .000#    __________________________________________________________________________               GDU STK PLT EAR RT  STA STK BRT GRN               SLK CNT HT  HT  LDG GRN LDG STK APP               % MN                   % MN                       % MN                           % MN                               % MN                                   % MN                                       % MN                                           % MN                                               % MN    __________________________________________________________________________    TOTAL SUM           1   97  100 98  93  105 83  96  112 100           2   94  99  97  94  88  86  100 110 101           LOCS               10  59  24  24  7   26  28  6   4           REPS               19  118 47  47  12  48  50  8   5           DIFF               3   1   1   1   17  3   3   2   1           PR > T               .001#                   .421                       .051*                           .481                               .126                                   .481                                       .078*                                           .182                                               .931    __________________________________________________________________________               DRP NLF GOS HD  GIB EYE ECB ECB ECB               EAR BLT WLT SMT ERS SPT DPE 1LF 25C               % MN                   ABS ABS ABS ABS ABS ABS ABS ABS    __________________________________________________________________________    TOTAL SUM           1   100 1.0 1.8 95.0                               5.5 6.3 93.6                                           4.7 4.3           2   100 1.8 4.3 75.0                               5.3 6.0 94.9                                           6.3 3.0           LOCS               17  2   3   2   2   3   4   3   3           REPS               25  4   6   6   3   6   8   3   3           DIFF               0   0.8 2.5 20.0                               0.3 0.3 1.2 1.7 1.3           PR > T               .999                   .500                       .013+                           .487                               .910                                   .635                                       .588                                           .370                                               .456    __________________________________________________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG

Strip Test Data for Hybrid 39K72

Comparison data was collected from strip tests that were grown byfarmers. Each hybrid was grown in strips of 4, 6, 8, 12, etc. rows infields depending on the size of the planter used. The data was collectedfrom strip tests that had the hybrids in the same area and weighed. Themoisture percentage was determined and bushels per acre was adjusted to15.5 percent moisture. The number of comparisons represent the number oflocations or replications for the two hybrids that were grown in thesame field in close proximity and compared.

Comparison strip testing was done between Pioneer Brand Hybrid 39K72 andPioneer Brand Hybrids 3979, 3984, and 3970. The comparisons come fromall the hybrid's adapted growing areas in the United States.

These results are presented in Table 3. As can be seen from the results,hybrid 39K72 has a yield advantage over all but one of the hybrids. Theaverage yield advantage is 2.0 bushels per acre. Hybrid 39K72 showed agreater income advantage to the farmer based on adjusted growth incomeover all but one of the hybrids compared. The average income advantageper acre was $6.97. Hybrid 39K72 also demonstrated a higher test weightthan all but one of the hybrids with an average advantage of 0.7 poundsper bushel. 39K72's yield and income advantage plus its advantage forother characteristics over these hybrids will make it an importantaddition for most of the areas where these hybrids are grown.

                                      TABLE 3    __________________________________________________________________________    1996 PERFORMANCE COMPARISON REPORT FOR CORN    1 YEAR SUMMARY OF ALL STANDARD TEST TYPES                         Income                             Pop Stand                                    Roots                                       Test    Brand      Product                   Yield                      Moist                         /Acre                             K/Acre                                 (%)                                    (%)                                       Wt    __________________________________________________________________________    PIONEER    39K72                   95.2                      24.0                         269.49                             26.2                                 91 99 54.3    PIONEER    3979                   90.9                      24.8                         255.95                             25.1                                 93 95 52.7    Advantage      4.3                      0.8                         13.54                             1.1 -2  4 1.6    Number of Comparisons                   37 37 37  21  21 14 31    Percent Wins   64 64 70  66   9 21 80    Probability of Difference                   99 99 99  99  90 69 99    PIONEER    39K72                   98.1                      24.3                         276.69                             25.7                                 87 99 54.7    PIONEER    3984                   89.8                      23.9                         253.59                             25.3                                 87 97 54.9    Advantage      8.3                      -0.4                         23.10                             0.4  0  2 -0.2    Number of Comparisons                   25 25 25  20  20 14 20    Percent Wins   88 52 84  45  50 21 20    Probability of Difference                   99 67 99  74  25 85 76    PIONEER    39K72                   92.9                      23.7                         263.43                             26.3                                 86 98 54.4    PIONEER    3970                   96.2                      24.7                         270.82                             26.1                                 82 98 53.9    Advantage      -3.3                      1.0                         -7.39                             0.2  4  0 0.5    Number of Comparisons                   45 45 45  24  24 17 38    Percent Wins   44 73 48  37  50 17 68    Probability of Difference                   97 99 90  41  90 29 99    PIONEER    39K72                   94.9                      24.0                         268.62                             26.1                                 88 99 54.4    WEIGHTED AVG   92.9                      24.5                         261.65                             25.5                                 87 97 53.7    Advantage      2.0                      0.5                         6.97                             0.6  1  2 0.7    Number of Comparisons                   107                      107                         107 65  65 45 89    Percent Wins   61 65 64  49  36 20 61    Probability of Difference                   96 99 99  99  44 86 99    __________________________________________________________________________     NOTE:     The probability values are useful in analyzing if there is a "real"     difference in the genetic potential of the products involved. High values     are desirable, with 95% considered significant for real differences.

Comparison of Key Characteristics for Hybrid 39K72

Characteristics of Pioneer Hybrid 39K72 are compared to Pioneer Hybrids3970, 3979, and 3984 in Table 4. The values given for most traits are ona 1-9 basis. In these cases 9 would be outstanding, while 1 would bepoor for the given characteristics. Table 4 shows that hybrid 39K72demonstrates excellent yield. Hybrid 39K72 exhibits superior rootlodging resistance to all hybrids and excellent early growth with ahigher early growth score than all of the hybrids compared. Hybrid39K72's excellent yield combined with its early growth and otherfavorable agronomic characteristics should make it an important hybridto its area of adaptation.

                                      TABLE 4    __________________________________________________________________________    Hybrid Patent Comparisons-Characteristics    Pioneer Hybrid 39K72 vs Pioneer Hybrids 3970, 3979 and 3984    __________________________________________________________________________            SILK               PHY                  GDU                     GDU            STA    VARIETY         CRM            CRM               CRM                  SILK                     PHY                        YLD                           D/D                              S/L                                 R/L                                    GRN                                       D/T    __________________________________________________________________________    39K72         75 78 76 970                     1760                        9  6  5  7  4  6    3970 77 79 78 990                     1810                        9  5  5  5  4  4    3979 76 76 75 950                     1730                        8  6  5  4  5  7    3984 75 74 73 920                     1680                        7  6  6  4  4  7    __________________________________________________________________________         TST   PLT                  EAR   BRT                           HSK                              NFL                                 GOS                                    HD GIB    VARIETY         WT E/G               HT HT D/E                        STK                           CV BLT                                 WLT                                    SMT                                       ERS    __________________________________________________________________________    39K72         7  9  5  5  5  7  4  2  2  7  5    3970 6  4  6  5  5  8  5  3  2  9  6    3979 4  5  6  6  5  6  4  3  4  5  6    3984 8  7  5  5  5  6  5  3  4  4  7    __________________________________________________________________________                      ECB                         ECB           VARIETY    1LF                         2SC    __________________________________________________________________________           39K72      5  4           3970       5  4           3979       7  4           3984       6  4    __________________________________________________________________________

INDUSTRIAL APPLICABILITY

This invention includes hybrid maize seed of 39K72 and the hybrid maizeplant produced therefrom. The foregoing was set forth by way of exampleand is not intended to limit the scope of the invention.

As used herein, the term plant includes plant cells, plant protoplasts,plant cell tissue cultures from which maize plants can be regenerated,plant calli, plant clumps, and plant cells that are intact in plants, orparts of plants, such as embryos, pollen, ovules, flowers, kernels,ears, cobs, leaves, seeds, husks, stalks, roots, root tips, anthers,silk and the like.

Duncan, Williams, Zehr, and Widholm, Planta, (1985) 165:322-332 reflectsthat 97% of the plants cultured which produced callus were capable ofplant regeneration. Subsequent experiments with both inbreds and hybridsproduced 91% regenerable callus which produced plants. In a furtherstudy in 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988),7:262-265 reports several media additions which enhance regenerabilityof callus of two inbred lines. Other published reports also indicatedthat "nontraditional" tissues are capable of producing somaticembryogenesis and plant regeneration. K. P. Rao, et al., Maize GeneticsCooperation Newsletter, 60:64-65 (1986), refers to somatic embryogenesisfrom glume callus cultures and B. V. Conger, et al., Plant Cell Reports,6:345-347 (1987) indicates somatic embryogenesis from the tissuecultures of maize leaf segments. Thus, it is clear from the literaturethat the state of the art is such that these methods of obtaining plantsare, and were, "conventional" in the sense that they are routinely usedand have a very high rate of success.

Tissue culture of maize is described in European Patent Application,publication 160,390, incorporated herein by reference. Maize tissueculture procedures are also described in Green and Rhodes, "PlantRegeneration in Tissue Culture of Maize," Maize for Biological Research(Plant Molecular Biology Association, Charlottesville, Virginia 1982, at367-372) and in Duncan, et al., "The Production of Callus Capable ofPlant Regeneration from Immature Embryos of Numerous Zea MaysGeneotypes," 165 Planta 322-332 (1985). Thus, another aspect of thisinvention is to provide cells which upon growth and differentiationproduce maize plants having the genotype of 39K72.

Maize is used as human food, livestock feed, and as raw material inindustry. The food uses of maize, in addition to human consumption ofmaize kernels, include both products of dry- and wet-milling industries.

Maize, including both grain and non-grain portions of the plant, is alsoused extensively as livestock feed, primarily for beef cattle, dairycattle, hogs, and poultry.

Industrial uses of maize include production of ethanol, maize starch inthe wet-milling industry and maize flour in the dry-milling industry.The industrial applications of maize starch and flour are based onfunctional properties, such as viscosity, film formation, adhesiveproperties, and ability to suspend particles. The maize starch and flourhave application in the paper and textile industries. Other industrialuses include applications in adhesives, building materials, foundrybinders, laundry starches, explosives, oil-well muds, and other miningapplications.

Plant parts other than the grain of maize are also used in industry.Stalks and husks are made into paper and wallboard and cobs are used forfuel and to make charcoal.

The seed of the hybrid maize plant and various parts of the hybrid maizeplant can be utilized for human food, livestock feed, and as a rawmaterial in industry.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity andunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the invention, as limited only bythe scope of the appended claims.

Applicant has nsde a deposit of at least 2500 seeds of Hybrid Maize Line39K72 with the American type Culture Collection (ATCC), Manassas, Va.20110 USA, ATCC Deposit No. 209831. The seeds deposited with the ATCC onMay 4, 1998 were taken from the deposit maintained by Pioneer Hi-BredIntemational, Inc., 700 Capital Square, 400 Locust Street, Des Moines,Iowa 50309-2340 since prior to the filing date of this application. Thisdeposit of the Hybrid Maize Line 39K72 will be maintained in the ATCCdepository, which is a public depository, for a period of 30 years, or 5years after the most recent request, or for the enforceable life of thepatent, whichever is longer, and will be replaced if it becomesnonviable during that period. Additionally, Applicant has satisfied allthe requirements of 37 C.F.R.§§1.801-1.809, including providing anindication of the viability of the sample. Applicant imposes norestrictions on the availability of the deposited material from theATCC; however, Applicant has no authority to waive any restrictionsimposed by law on the transfer of biological material or itstransportation in commerce. Applicant does not waive any infringement ofits rights granted under this patent.

What is claimed is:
 1. Hybrid maize seed designated 39K72,representative seed of said hybrid 39K72 having been deposited underATCC accession number
 209831. 2. A maize plant, or its parts, producedby the seed of claim
 1. 3. Pollen of the plant of claim
 2. 4. An ovuleof the plant of claim
 2. 5. A tissue culture of regenerable cells of ahybrid maize plant 39K72, representative seed of said hybrid maize plant39K72 having been deposited under ATCC accession number 209831, whereinthe tissue regenerates plants capable of expressing all themorphological and physiological characteristics of said hybrid maizeplant 39K72.
 6. A tissue culture according to claim 5, the cells beingfrom a tissue selected from the group consisting of leaves, pollen,embryos, roots, root tips, anthers, silks, flowers, kernels, ears, cobs,husks, and stalks.
 7. A maize plant, or its parts, regenerated from thetissue culture of claim 5 and capable of expressing all themorphological and physiological characteristics of hybrid maize plant39K72, representative seed having been deposited under ATCC accessionnumber 209831.